perception

perception,

in psychology, mental organization and interpretation of sensory information. The GestaltGestalt[Ger.,=form], school of psychology that interprets phenomena as organized wholes rather than as aggregates of distinct parts, maintaining that the whole is greater than the sum of its parts......Click the link for more information. psychologists studied extensively the ways in which people organize and select from the vast array of stimuli that are presented to them, concentrating particularly on visual stimuli. Perception is influenced by a variety of factors, including the intensity and physical dimensions of the stimulus; such activities of the sense organs as effects of preceding stimulation; the subject's past experience; attention factors such as readiness to respond to a stimulus; and motivation and emotional state of the subject. Stimulus elements in visual organization form perceived patterns according to their nearness to each other, their similarity, the tendency for the subject to perceive complete figures, and the ability of the subject to distinguish important figures from background. Perceptual constancy is the tendency of a subject to interpret one object in the same manner, regardless of such variations as distance, angle of sight, or brightness. Through selective attention, the subject focuses on a limited number of stimuli, and ignores those that are considered less important. Depth perception, considered to be innate in most animals, is produced by a variety of visual cues indicating perspective, and by a slight disparity in the images of an object on the two retinas. An absolute threshold is the minimal physical intensity of a stimulus that a subject can normally perceive, whereas a difference threshold is the minimal amount of change in a stimulus that can be consciously detected by the subject. Recent studies have shown that stimuli are actually perceived in the brain, while sensory organs merely gather the signals. William Dobelle's research, for instance, has offered significant hope for the blind.

Perception

Those subjective experiences of objects or events that ordinarily result from stimulation of the receptor organs of the body. This stimulation is transformed or encoded into neural activity (by specialized receptor mechanisms) and is relayed to more central regions of the nervous system where further neural processing occurs. Most likely, it is the final neural processing in the brain that underlies or causes perceptual experience, and so perceptionlike experiences can sometimes occur without external stimulation of the receptor organs, as in dreams.

In contemporary psychology, interest generally focuses on perception or the apprehension of objects or events, rather than simply on sensation or sensory process. While no sharp line of demarcation between these topics exists, it is fair to say that sensory qualities are generally explicable on the basis of mechanisms within the receptor organ, whereas object and event perception entails higher-level activity of the brain. SeeHearing (human), Sensation, Vision

Since objects or events are not experienced only through vision, the term perception obviously applies to other sense modalities as well. Certainly things and their movement may be experienced through the sense of touch. Such experiences derive from receptors in the skin (tactile perception), but more importantly, from the positioning of the fingers with respect to one another when an object is grasped, the latter information arising from receptors in the muscles and joints (haptic or tactual perception). The position of the parts of the body are also perceived with respect to one another whether they are stationary (proprioception) or in motion (kinesthesis), and the position of the body is experienced with respect to the environment through receptors sensitive to gravity such as those in the vestibular apparatus in the inner ear. Auditory perception yields recognition of the location of sound sources and of structures such as melodies and speech. Other sense modalities such as taste (gustation), smell (olfaction), pain, and temperature provide sensory qualities but not perceptual structures as do vision, audition, and touch, and thus are usually dealt with as sensory processes. SeeOlfaction, Pain, Proprioception

Constancy

By and large, these perceptual properties of objects remain remarkably constant despite variations in distance, slant, and retinal locus caused by movements of the observer. This fact, referred to as perceptual constancy, is perhaps the hallmark of perception and more than any other, serves to characterize the field of perception.

Examples of perceptual constancy are: size (except at very great distances, an object appears the same size whether seen nearby or far away, although the size of its image on the retina can be very different); shape (a circle seen from the side is perceived as a circle, although it appears as an ellipse on the retina); orientation (objects appear to keep the same orientation in space, independently of the orientation of the observer's head); and position (a fixed object remains perceived as stationary even when its image on the retina moves because of eye or head movements).

A central problem is whether the perception of properties such as form and depth is innately determined or is based on past experience. By “innate” it is meant that the perception is the result of evolutionary adaptation and thus is present at birth or when the necessary neural maturation has occurred. By “past experience” it is meant that the perception in question is the end result of prior exposure to certain relevant patterns or conditions, a kind of learning process. Despite centuries of discussion of this problem, and considerable experimental work, there is still no final answer to the question. It now seems clear that certain kinds of perception are innate, but equally clear that past experience also is a determining factor. SeeIntelligence

perception

the reception and interpretation of stimuli. This involves sensory mechanisms and cognitive appraisal, and is influenced by prior learning experiences, emotional state, and current expectations. The significance of the term for sociologists is in acknowledgement of the individual interpretation of events which is socially and culturally influenced. Thus ATTITUDE, RACISM, PREJUDICE, STEREOTYPING have a perceptual aspect. see also GESTALT THEORY.

Perception

a complex system of receiving and transforming information that provides an organism with a reflection of objective reality and an orientation toward the surrounding world.

With sensation, perception is the starting point of cognition, supplying primary material derived from the senses. Since it is a necessary condition for cognition, perception in this process is always mediated in one way or another by the activity of thought and is verified by practical experience. Without such mediation and verification, perception can act as a source of both genuine knowledge and error and illusion.

Included in perception are discovery of an object within a perceived field, differentiation of specific signs in the object, discrimination in the object of informative content related to the goal of action, and familiarization with the discriminated content and the formation of an image (or “operative unit” of perception).

A large contribution in the development of scientific knowledge about perception has been made by philosophers, astronomers, physicists, and artists, including Aristotle, Democritus, J. Kepler, Leonardo da Vinci, M. V. Lomonosov, H. Helmholtz, and many others. The attention of psychologists and physiologists was long focused on the study of the sensory effects that arise under the influence of various objective stimuli, whereas the process of perception itself remained outside the limits of research. The methodology of such an approach was based on sensationalism in the theory of knowledge, especially as developed by J. Locke and the French materialists (P. Cabanis and E. Condillac). In psychology this approach received its clearest expression in the concept of perception according to which the sensory image comes into being as the result of stimuli by external agents on the percipient sense organs of a passively contemplating subject. The limited nature of such an approach—that is, the ignoring of the subject’s activity, the study of only the results of the process of perception, and the representation of the group of analyzers in the cortex as a substratum of sensory processes, as a place where there supposedly occurs the transformation of neural processes into ideational psychic images—all this created practical difficulties for developing methods to control the processes of perception in order to perfect and develop it. Theoretically, moreover, it led either to various subjective and idealistic theories or to a rejection of the scientific explanation of perception.

A decisive step in overcoming the passive “receptor” concept was made by Soviet psychologists, who, by proceeding from the methodology of dialectical materialism and the Sechenov school’s understanding of the reflex nature of sensory processes, regarded perception as a unique activity directed at examining the perceived object and at creating a copy, or representation of it. At present, research on perception is being conducted in several fields on the various levels of the processes of receiving and transforming information. At the entry level of percipient systems (the retina of the eye, the organ of Corti of the ear, etc.) studies are being carried out on the anatomical-morphological, biophysical, and electrophysiological properties of the activity of receptors. Perception is also being studied on the neural, psycho-physiological, psychological, and sociopsychological levels. In cybernetics and bionics a great deal of research is being done on the creation of technical setups that would imitate the operation of the sense organs. The results of various types of studies on perception are published in dozens of journals devoted primarily to the problems of perception. It must, however, be emphasized that thus far there has been no successful construction of a standard theory of perception that would integrate the results of numerous investigations. Great difficulties have been encountered in efforts to model such properties of perception as meaningfulness, constancy, and objectness.

According to current concepts, the totality of the processes of perception ensures the subjective, prejudiced, and nevertheless adequate reflection of objective reality. The adequacy of the image of perception (its correspondence to actuality) is achieved owing to the fact that in its formation there occurs a reconstitution (A. N. Leont’ev)—that is, an adjustment of the percipient systems to the properties of the stimulus. For example, in the movement of the hand as it feels an object, in the movement of the eye as it follows a contour, and in the movements of the larynx as it reproduces a sound, a copy comparable to the original is created. Signs of disparity entering the nervous system correct the image that is being formed and hence correct the practical actions being carried out on the basis of this image. Consequently, perception represents a kind of self-regulating process with a feedback mechanism and the ability to acquiesce to the special characteristics of the reflected object.

An important property of perception is the capacity to reconstruct the sensory models of the outside world that act upon the subject and to change the methods of their construction and identification. One and the same object may serve as the prototype for many perceptual models. In the process of their formation they become defined more accurately, and from the object stock properties and signs are deduced, which results in a perception of the world as it exists in fact. The purposive processes of perception (perceptual activities) appear in their developed, external form only at the early stages of ontogenesis, when their structure and their role in forming the images of perception are most clearly revealed. They subsequently undergo a number of consecutive changes and curtailments until they acquire the form of the instantaneous act of “discerning” an object. This was described by Gestalt psychologists, who erroneously conceived it to be the initial, genetically primary form of perception.

Any living system possesses a developed alphabet—that is, a definite complex of images or perceptual models. During construction of the image of an object, the correspondence of the percipient systems to the characteristics of the stimulus is established; during identification or operation by means of the images that are formed, the characteristics and direction of the process subchange substantially (A. V. Zaporozhets). That is, on one hand, the subject reconstructs with the aid of his own movements and actions a certain representation, or image, of the perceived object; on the other, there occurs a recoding, or translation, of the received information into the “language” of the operative units of perception or perceptual models that have already been mastered by the subject. The second aspect expresses the fact that simultaneous with the establishment of the correspondence of the percipient systems of the subject to the object, a correspondence of the object to the subject is also established, and it is only this dual transformation that leads to the formation of a sound, adequate, and nevertheless subjective image of objective reality.

In well-developed processes of perception there are specialized activities on the basis of which the subject can discriminate informational content and associate the object that has been presented with his accumulated perceptual models. He can then properly implement the process of association and final identification and referral of objects to one class or another—that is, categorization. The process of identification requires considerably less time than the process of forming an image: in order to associate and identify, it is only necessary to extract certain stock properties and signs from the presented object. The percipient systems (this is especially evident in the case of vision) have a certain “manipulative” capacity: within a short time the subject imitates the processes of forming the image, as if he were examining the object from various sides and finding that point at which there is maximum facilitation of association and identification.

In the total act of behavior there exists yet another unique form of reconstitution of the correspondence: the processes of restructuring and transforming an image in order to present information in a form suitable for making a decision. In this process there is the resolution of the problem of a change in reality that is adequate for plans and behavior goals. Preceding such a change is the transformation of the image of a situation, which, as a rule, is not conscious but which nevertheless contributes substantially to the problems of life that confront the subject. Perception is not the passive copying of reality but rather an active, creative process of cognition.

The study of perception has significance in aesthetics, teacher education, sports, and so forth, and specific problems of perception are dealt with in each of these fields.

perception

[pər′sep·shən]

(physiology)

Recognition in response to sensory stimuli; the act or process by which the memory of certain qualities of an object is associated with other qualities impressing the senses, thereby making possible recognition of the object.

perception

1.Biology the process by which an organism detects and interprets information from the external world by means of the sensory receptors

2.Law the collection, receipt, or taking into possession of rents, crops, etc.

To the extent that one would like to be able to conceive causal relations, mathematical entities, and moral facts as objects of perception, Church's theory of perception receives support in providing resources to do so.

The purpose of the current action research study was to explore students' perceptions of student-led conferences and the significance of student-set goals versus teacher-set goals on the learning processes.

African Business magazine has been campaigning long and hard to try and change some of the negative perception of our continent in those countries where we circulate--and we are glad to report that we have scored some remarkable successes.

Come March, the perceptions and preconceived notions fly as easily as a line drive in the Arizona sun, and why bother playing the season, since we know exactly what's going to go down from spring training until the final, awkward words of congratulations tumble from the mouth of the commissioner on a cool October evening.

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